Ancient origin of the CAG expansion causing Huntington disease in a Spanish population.
Hum Mutat
; 25(5): 453-9, 2005 May.
Article
em En
| MEDLINE
| ID: mdl-15832309
ABSTRACT
Huntington disease (HD) is an autosomal dominant neurodegenerative disorder characterized clinically by progressive motor impairment, cognitive decline, and emotional deterioration. The disease is caused by the abnormal expansion of a CAG trinucleotide repeat in the first exon of the huntingtin gene in chromosome 4p16.3. HD is spread worldwide and it is generally accepted that few mutational events account for the origin of the pathogenic CAG expansion in most populations. We have investigated the genetic history of HD mutation in 83 family probands from the Land of Valencia, in Eastern Spain. An analysis of the HD/CCG repeat in informative families suggested that at least two main chromosomes were associated in the Valencian population, one associated with allele 7 (77 mutant chromosomes) and one associated with allele 10 (two mutant chromosomes). Haplotype A-7-A (H1) was observed in 47 out of 48 phase-known mutant chromosomes, obtained by segregation analysis, through the haplotype analysis of rs1313770-HD/CCG-rs82334, as it also was in 120 out of 166 chromosomes constructed by means of the PHASE program. The genetic history and geographical distribution of the main haplotype H1 were both studied by constructing extended haplotypes with flanking short tandem repeats (STRs) D4S106 and D4S3034. We found that we were able to determine the age of the CAG expansion associated with the haplotype H1 as being between 4,700 and 10,000 years ago. Furthermore, we observed a nonhomogenous distribution in the different regions associated with the different extended haplotypes of the ancestral haplotype H1, suggesting that local founder effects have occurred.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Nucleares
/
Doença de Huntington
/
Evolução Molecular
/
Expansão das Repetições de Trinucleotídeos
/
Proteínas do Tecido Nervoso
Limite:
Humans
País/Região como assunto:
Europa
Idioma:
En
Revista:
Hum Mutat
Assunto da revista:
GENETICA MEDICA
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Espanha